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Selected AbstractsCongenic Strains of Mice for Verification and Genetic Decomposition of Quantitative Trait Loci for Femoral Bone Mineral Density,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 2 2003Kathryn L Shultz Abstract Peak femoral volumetric bone mineral density (femoral bone mineral density) in C57BL/6J (B6) 4-month-old female mice is 50% lower than in C3H/HeJ (C3H) and 34% lower than in CAST/EiJ (CAST) females. Genome-wide analyses of (B6 × C3H)F2 and (B6 × CAST)F2 4-month-old female progeny demonstrated that peak femoral bone mineral density is a complex quantitative trait associated with genetic loci (QTL) on numerous chromosomes (Chrs) and with trait heritabilities of 83% (C3H) and 57% (CAST). To test the effect of each QTL on femoral bone mineral density, two sets of loci (six each from C3H and CAST) were selected to make congenic strains by repeated backcrossing of donor mice carrying a given QTL-containing chromosomal region to recipient mice of the B6 progenitor strain. At the N6F1 generation, each B6.C3H and B6.CAST congenic strain (statistically 98% B6-like in genomic composition) was intercrossed to obtain N6F2 progeny for testing the effect of each QTL on femoral bone mineral density. In addition, the femoral bone mineral density QTL region on Chr 1 of C3H was selected for congenic subline development to facilitate fine mapping of this strong femoral bone mineral density locus. In 11 of 12 congenic strains, 6 B6.C3H and 5 B6.CAST, femoral bone mineral density in mice carrying c3h or cast alleles in the QTL regions was significantly different from that of littermates carrying b6 alleles. Differences also were observed in body weight, femoral length, and mid-diaphyseal periosteal circumference among these 11 congenic strains when compared with control littermates; however, these latter three phenotypes were not consistently correlated with femoral bone mineral density. Analyses of eight sublines derived from the B6.C3H-1T congenic region revealed two QTLs: one located between 36.9 and 49.7 centiMorgans (cM) and the other located between 73.2 and 100.0 cM distal to the centromere. In conclusion, these congenic strains provide proof of principle that many QTLs identified in the F2 analyses for femoral bone mineral density exert independent effects when transferred and expressed in a common genetic background. Furthermore, significant differences in femoral bone mineral density among the congenic strains were not consistently accompanied by changes in body weight, femur length, or periosteal circumference. Finally, decomposition of QTL regions by congenic sublines can reveal additional loci for phenotypes assigned to a QTL region and can markedly refine genomic locations of quantitative trait loci, providing the opportunity for candidate gene testing. [source] Effect of exogenous glutamate and N-Methyl-D-aspartic acid on spontaneous activity of isolated human ureterINTERNATIONAL JOURNAL OF UROLOGY, Issue 9 2007Slobodan M Jankovic Objectives: While the neurotransmitter role of glutamate in the gastrointestinal tract has been shown, its effects on smooth muscle of the human ureter have not previously been investigated. In our study we have investigated the effects of exogenous glutamate on the spontaneous activity of isolated human ureter, taken from 14 adult patients after nephrectomy. Methods: The segment of ureter, excised 3 cm distal from the pyeloureteral junction, was isolated in an organ bath. Both longitudinal tension and intraluminal pressure of the segment were recorded simultaneously. Results: Glutamate administered in the lumen of the isolated ureteral segments (7.8 × 10,7 M/L,3.5 × 10,2 M/L) was ineffective. When added to the isolated organ bath from the serous side of the ureteral segment, glutamate (7.9 × 10,6 M/L,10.6 × 10,3 M/L) and N-Methyl-D-aspartic acid (NMDA) (9.1 × 10,8 M/L,3.1 × 10,5 M/L) produced a concentration-dependent increase in spontaneous activity of the isolated preparations, while kainic acid (6.3 × 10,8 M/L,10.5 × 10,5 M/L) and (+/,)- trans -1-Aminocyclopentane- trans -1,3-dicarboxylic acid (ACPD) (7.7 × 10,8 M/L ,6.5 × 10,5 M/L) were ineffective. Conclusions: The results of our study suggest that an excitatory neurotransmitter glutamate stimulates spontaneous activity of the human ureter through activation of NMDA ionotropic receptors, located on smooth muscle cells or intramural nerve fibers [source] Age Trends in Femur Stresses From a Simulated Fall on the Hip Among Men and Women: Evidence of Homeostatic Adaptation Underlying the Decline in Hip BMDJOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2006Thomas J Beck ScD Abstract Age trends in proximal femur stresses were evaluated by simulating a fall on the greater trochanter using femur geometry from hip DXA scans of 5334 white men and women in the NHANES III survey. Expansion of femur outer diameter seems to counter net bone loss so that stresses remain similar across age groups, but stresses are higher in older women than in older men. Introduction: The age decline in hip BMD is caused by both bone loss and expansion of outer diameter that increases the region size over which mass is measured in a DXA scan. Because expansion has an opposing effect on structural strength, it may be a homeostatic adaptation to net bone loss to ensure that load stresses are kept within a narrow range. Materials and Methods: Age trends in femur stresses were evaluated with an engineering beam simulation of a fall on the greater trochanter. Hip geometry was extracted from hip DXA scans using the Hip Structure Analysis (HSA) software on 2613 non-Hispanic white men and 2721 women from the third National Health and Nutrition Examination Survey (NHANES III). Using body weight as load, stresses were computed on the inferior-medial and superior-lateral femur neck at its narrowest point and the medial and lateral shaft 2 cm distal to the midpoint of the lesser trochanter. Stresses and the underlying geometries in men and women >50 years oaf age were compared with those 20,49 years of age. Results: Compared with men <50 years of age, stresses in older men were 6% lower on both surfaces of the shaft, 4% lower on the inferior-medial neck, and not different on the superior-lateral neck. In women >50 years of age, stresses on the proximal shaft and inferior-medial neck remained within 3% of young values but were 13% greater on the superior-lateral neck. Neck stresses in young women were lower on the superior-lateral than the inferior-medial neck, but lateral stress increased to the level on the medial surface in older women. Stresses were higher in women than in men, with a greater gender difference in those >50 years of age. Conclusions: We conclude that femur expansion has a homeostatic effect in men and women that opposes bone loss so that stresses change little with age. Because expansion preserves stresses with progressively less bone mass, the process may reduce structural stability in the femoral neck under fall conditions, especially in the elderly female. [source] Structural Trends in the Aging Femoral Neck and Proximal Shaft: Analysis of the Third National Health and Nutrition Examination Survey Dual-Energy X-Ray Absorptiometry Data,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 12 2000Thomas J. Beck Abstract Hip scans of U.S. adults aged 20,99 years acquired in the Third National Health and Nutrition Examination Survey (NHANES III) using dual-energy X-ray absorptiometry (DXA) were analyzed with a structural analysis program. The program analyzes narrow (3 mm wide) regions at specific locations across the proximal femur to measure bone mineral density (BMD) as well as cross-sectional areas (CSAs), cross-sectional moments of inertia (CSMI), section moduli, subperiosteal widths, and estimated mean cortical thickness. Measurements are reported here on a non-Hispanic white subgroup of 2719 men and 2904 women for a cortical region across the proximal shaft 2 cm distal to the lesser trochanter and a mixed cortical/trabecular region across the narrowest point of the femoral neck. Apparent age trends in BMD and section modulus were studied for both regions by sex after correction for body weight. The BMD decline with age in the narrow neck was similar to that seen in the Hologic neck region; BMD in the shaft also declined, although at a slower rate. A different pattern was seen for section modulus; furthermore, this pattern depended on sex. Specifically, the section modulus at both the narrow neck and the shaft regions remains nearly constant until the fifth decade in females and then declined at a slower rate than BMD. In males, the narrow neck section modulus declined modestly until the fifth decade and then remained nearly constant whereas the shaft section modulus was static until the fifth decade and then increased steadily. The apparent mechanism for the discord between BMD and section modulus is a linear expansion in subperiosteal diameter in both sexes and in both regions, which tends to mechanically offset net loss of medullary bone mass. These results suggest that aging loss of bone mass in the hip does not necessarily mean reduced mechanical strength. Femoral neck section moduli in the elderly are on the average within 14% of young values in females and within 6% in males. [source] Soft tissue landmark for ultrasound identification of the sciatic nerve in the infragluteal region: the tendon of the long head of the biceps femoris muscleACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 7 2009J. BRUHN Background and objectives: The sciatic nerve block represents one of the more difficult ultrasound-guided nerve blocks. Easy and reliable internal ultrasound landmarks would be helpful for localization of the sciatic nerve. Earlier, during ultrasound-guided posterior approaches to the infragluteal sciatic nerve, the authors recognized a hyperechoic structure at the medial border of the long head of biceps femoris muscle (BFL). The present study was performed to determine whether this is a potential internal landmark to identify the infragluteal sciatic nerve. Methods: The depth and the thickness of this hyperechoic structure, its relationship with the sciatic nerve and the ultrasound visibility of both were recorded in the proximal upper leg of 21 adult volunteers using a linear ultrasound probe in the range of 7,13 MHz. The findings were verified by an anatomical study in two cadavers. Results: The hyperechoic structure at the medial border of the BFL extended in a dorsoventral direction between 1.4±0.6 cm (mean±SD) and 2.8±0.8 cm deep from the surface, with a width of 2.2±0.9 mm. Between 2.6±0.9 and 10.0±1.5 cm distal to the subgluteal fold, the sciatic nerve was consistently identified directly at the ventral end of the hyperechoic structure in all volunteers. The anatomical study revealed that this hyperechoic structure corresponds to tendinous fibres inside and at the medial border of the BFL. Conclusion: The hyperechoic BFL tendon might be a reliable soft tissue landmark for ultrasound localization of the infragluteal sciatic nerve. [source] Peritoneal mesothelioma presenting as an acute surgical abdomen due to jejunal perforationJOURNAL OF DIGESTIVE DISEASES, Issue 4 2007Nikolaos S SALEMIS BACKGROUND: Peritoneal mesothelioma is a rare disease associated with poor prognosis. Acute abdomen as the first presentation is an extremely rare occurrence. We report an exceptional case of a patient who was found to have a jejunal perforation due to infiltration of peritoneal mesothelioma. METHODS: A 62-year-old man was admitted with clinical signs of peritonitis. Computerized tomographic scans showed a mass distal to the ligament of Treitz, thickening of the mesentery and a small amount of ascites. RESULTS: Emergency laparotomy revealed a perforated tumor 15 cm distal to the ligament of Treitz and diffuse peritoneal disease. Segmental small bowel resection and suboptimal cytoreduction were performed. Histopathology and immunohistochemistry showed infiltration of malignant mesothelioma. During the postoperative period pleural mesothelioma was also diagnosed. Despite adjuvant chemotherapy, the patient died of disseminated progressive disease 7 months after surgery. CONCLUSIONS: Peritoneal mesothelioma is a rare malignancy with grim prognosis. Small bowel involvement is a poor prognostic indicator. Our case of a small bowel perforation due to direct infiltration by peritoneal mesothelioma appears to be the first reported in the English literature. [source] Anterior sciatic nerve block , new landmarks and clinical experienceACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2005M. Wiegel Background: Anterior sciatic nerve blocks can be complicated by several problems. Pain can be caused by bony contacts and, in obese patients, identification of the landmarks is frequently difficult. Methods: In a first step, 100 normal anterior-posterior pelvic X-rays were analyzed. The landmarks of the classical anterior approach were drawn on these X-rays and assessed for their sufficiency. Then, in a prospective case study, 200 consecutive patients undergoing total knee replacement were investigated. These patients received femoral and sciatic nerve catheters for postoperative pain management. Using modified anatomical landmarks, sciatic nerve catheters were inserted 5 cm distal from the insertion site of the femoral nerve block perpendicularly in the midline of the lower extremity. This midline connected the insertion site of the femoral nerve catheter to the midpoint between the medial and lateral epicondyle. Correct catheter positioning was verified by magnetic resonance imaging (MRI) in six patients. Results: Evaluation of pelvic X-rays showed that puncture following the classical landmarks pointed in 51% at the lesser trochanter, in 5% medial to the lesser trochanter and in 42% directly at the femur. In the latter patients, location of the sciatic nerve would have been difficult or even impossible. Using our modified anterior approach, the sciatic nerve could be blocked in 196 patients (98%). In nine patients (4.5%) blockade of the posterior femoral cutaneous nerve failed. Vascular puncture happened in 10 (5%) and bony contact in 35 patients (17.5%). Median puncturing depth was 9.5 (7.5,14) cm. Correct sciatic nerve catheter positioning was verified in all patients who underwent MRI. Conclusion: Our landmarks for locating the sciatic nerve help to avoid bony contacts and thereby reduce pain during puncture. Our method reliably enabled catheter placement. [source] Oral administration of tacrolimus in the presence of jejunostomy after liver transplantationPEDIATRIC TRANSPLANTATION, Issue 3 2001Toshimichi Hasegawa Abstract: The feasibility of oral administration of tacrolimus in the presence of an intestinal stoma after liver transplantation (LTx) has not been adequately demonstrated. A 10-month-old girl underwent LTx with biliary reconstruction using a Roux-en Y loop. She developed intestinal perforation and underwent a jejunostomy at 40,50 cm distal to the jejunojejunostomy of the Roux-en Y loop on day 8 post-LTx. Tacrolimus was given twice daily via a nasogastric tube or orally; the initial dose of tacrolimus was 0.10 mg/kg/day. Until the time of intestinal perforation, the trough level of tacrolimus ranged from 13.0 to 19.6 ng/mL. The dose-normalized trough concentration (DNTC) of tacrolimus ranged from 130 to 196 ng.kg.daypermg.mL (control: 80,145 ng.kg.daypermg.mL). For a 2-week period when the patient was septic, the tacrolimus dose was reduced to 0.05 mg/kg/day, with a subsequent trough level of 3.6,5.1 ng/mL (DNTC: 72,102 ng.kg.daypermg.mL). After 3 weeks, the dose was increased to 0.175 mg/kg/day with the disappearance of infection; the trough level ranged from 8.5 to 9.7 ng/mL with a peak level of 26.3 ng/mL (DNTC: 48.5,55.4 ng.kg.daypermg.mL). After the initiation of oral feeding, the dose was slightly increased to 0.20 mg/kg/day with the trough level ranging from 8.1 to 9.8 ng/mL (DNTC: 40.5,49 ng.kg.daypermg.mL). After closure of the jejunostomy, the dose of tacrolimus was reduced to 0.075 mg/kg/day to maintain the same trough level (7.9,9.1 ng/mL) and the DNTC ranged from 105 to 121 ng.kg.daypermg.mL. In conclusion, oral administration of tacrolimus may achieve the therapeutic level, even in the presence of jejunostomy after LTx, although the bioavailability is decreased. [source] The Anatomic Relationship Between the Common Femoral Artery and Common Femoral Vein in Frog Leg Position Versus Straight Leg Position in Pediatric PatientsACADEMIC EMERGENCY MEDICINE, Issue 7 2009Jennifer W. Hopkins MD Abstract Background:, Overlap of the femoral artery (FA) on the femoral vein (FV) has been shown to occur in pediatric patients. This overlap may increase complications such as arterial puncture and failed insertions of central venous lines (CVLs). Knowledge of the anatomic relationship between the FV and FA may be important in avoiding these complications. Objectives:, The objective was to evaluate the anatomic relationship of the FA and FV in straight leg position and frog leg position. Methods:, This was a prospective, descriptive study of a convenience sample of 80 total subjects (16 subjects from each of five predetermined stratified age groups). Each subject underwent a standardized ultrasound examination in both the straight and the frog leg positions. The location of the FA in relation to the FV was measured at three locations: immediately distal, 1 cm distal, and 3 cm distal to the inguinal ligament. Overlap of the FA on the FV and the diameter of the FV was noted at each location. Measurements were repeated in both the straight leg and the frog leg positions. Results:, For the left leg, immediately distal to the inguinal ligament, the FV was overlapped by the FA in 36% of patients in straight leg position and by 45% of patients in frog leg position. At 1 cm distal to the ligament, overlap was observed in 75% of patients in straight leg position and 88% of patients in the frog leg position. At 3 cm distal to the ligament, overlap was observed in 93% of patients in straight leg position and 86% of patients in the frog leg position. The percentage of vessels with overlap was similar in the right leg at each location for both the straight and the frog leg positions. Pooled mean (±SD) FV diameters for the left leg immediately distal to the inguinal ligament were 0.64 (±0.23) cm in the straight leg position and 0.76 (±0.28) cm in the frog leg position; at 1 cm distal to the ligament, 0.66 (±0.23) and 0.78 (±0.29) cm; and at 3 cm distal to the ligament, 0.65 (±0.27) and 0.69 (±0.29) cm. FV diameters for the right leg were similar to the left. Conclusions:, A significant percentage of children have FAs that overlap their FVs. This overlap may be responsible for complications such as FA puncture with CVL placement. Ultrasound-guided techniques may decrease these risks. Placing children in the frog leg position increases the diameter of the FV visualized on ultrasound. [source] Deep fascia on the dorsum of the ankle and foot: Extensor retinacula revisitedCLINICAL ANATOMY, Issue 2 2007Marwan F. Abu-Hijleh Abstract This study revisits the anatomy of the deep fascia over the distal leg, ankle, and dorsum of the foot. The arrangement of the deep fascia in these regions was recorded in 14 lower limbs of adult cadavers using photographs and drawings. The fascial layer from all three sites was subsequently removed in toto, and serial thickness measurements were made along its entire length. In addition, fiber disposition was studied under polarized light, and sections were stained to demonstrate collagen. The arrangement of deep fascia is complex. A common and novel finding at all levels is a crisscross, lattice-like arrangement of fibers. There was little evidence of the clearly defined sturdy band of the superior extensor retinaculum (SER) or of the Y-shaped inferior retinaculum (IER) commonly illustrated in topographical anatomy texts. The SER is a complex area with several thickenings commencing about 3 cm proximal to the tip of the lateral malleolus and gradually increasing to reach a maximum of 270 ,m about 5 cm above the malleolus, then gradually returning to original thickness, about 9 cm above the malleolus. Fibers crossing diagonally to each other are a feature of the region. The IER characteristically has two forms: either a cross-shaped band (9 specimens) or a thickened "node" with small extensions radiating toward the malleoli (5 specimens), located about 1,2 cm distal to the lateral malleolus and centred over the common tendon of extensor digitorum where it has maximum thickness (430 ,m). The deep fascia is thickened and firmly attached over both malleoli and to the tarsals and metatarsals along both borders of the foot. In general, the deep fascial structures were thicker in males than those in females. Clin. Anat. 20:186,195, 2007. © 2006 Wiley-Liss, Inc. [source] | ||||||||||